Difference Between Cloud Computing and Grid Computing

Parameter	Grid Computing	Cloud Computing
Definition	It is a collection of heterogeneous Computers from different locations to achieve a common goal.	It is the delivery of computing as a service rather than a product, where resources, software, and information are provided to Computers and Other devices as a utility.
Platform	It makes use of heterogeneous Computers to run.	It makes use of Homogeneous computers to run.
Focused on	Intensive Calculus	Standard and intensive cloud.
Visualization	Not Much Reliable	Reliable
Performance	High	Less than Grid
Research Community	Grid is distributed and has multiple user communities and is grouped in virtual organization.	It has generally one research community and a common group of system administrators that take care of entire domain.
Funds	Grid is generally funded by local, national and international levels.	Cloud is generally funded by its users only.
Economy	It’s not economic to store small files on grid.	It’s economic to store small files on cloud.

Difference Between MAC and IP address

Parameter	MAC Address	IP Address
Acronym for	media access control address	Internet Protocol Address
Used for	It is a unique identifier that is assigned to network interfaces for communicating on the physical network segments.	It is a numerical value that is assigned to all the participating devices in a network. i.e. Servers, Computers, Printers, WAP, Laptops etc.
Provided BY	It is generally provided by the manufacturer of the NIC cards and is stored in its hardware.	It is provided by the ISP (Internet Service Provider) or by the Network Administrator.
Length	It is 48 bit address which contains 6 groups of 2 hexadecimal digits, separated by either hyphens (-) or colons (:) E.g. 00:FF:FF:AB:BB:AA Or 00-FF-FF-AB-BB-AA	IPv4 uses 32 bit address in dotted notations, whereas IPv6 Uses 128 bit address in hexadecimal notations. e.g. IPv4      192.168.1.1 IPv6    FFFE:F200:3204:0B00: 0122:4555:8001:AB00

Difference Between OSI and TCP/IP Reference Models

Parameter	OSI Reference Model	TCP/IP Model
Clarification between Services, Interfaces and Protocols	OSI Model clearly distinguishes between Services, Interfaces and Protocols. Each layer performs some services to upper layers, layer interfaces tells the processes above it how to access it, and different protocols are used by different layers as per their needs until a job is not finished.	TCP/IP model does not clearly distinguish between Services, Interfaces and Protocols.
Protocol Biasing	This model is not biased for a particular set of protocols and was developed before corresponding protocols invention.	This Model was developed after inventing corresponding protocols and just was description of existing protocols.
Layers	It is a Seven Layered Model. Which are as follows : a)      Physical Layer b)      Data Link Layer c)       Network Layer d)      Transport Layer e)      Session Layer f)       Presentation Layer g)      Application Layer	It is a 4 Layered Model. Which are as follows: a)      Subnet Layer b)      Internet Layer c)       Transport layer d)      Application Layer
Entity Approaches	OSI uses Horizontal approach in creating application entities. I.e. Strict hierarchy of layers is followed by distributed applications which are constructed from common toolbox of Application Service Elements (ASEs).	TCP/IP uses vertical approach in creating application entities. i.e.  In TCP/IP each application entity contains all the functions that it needs to support a distributed communication system.

Difference Between Single Mode and Multi Mode Fiber

Parameter	Single Mode Fiber	Multi-Mode Fiber
Core Size	It has very small sized core and allows only one mode of light to propagate.	It has large Sized core and allows multiple mode of light to propagate.
Sources	1310+ nm lasers 1 and 10 Gb/s 1 Gb/s + w/ DWDM High precision packaging	850 nm and 1310 nm LEDs 850 nm lasers at 1 & 10 Gb/s Low precision packaging
Distance Support	This Cable is used to transmit data to long distances. Because as the light passes through the core, the number of light reflections created decreases which decreases attenuation and creates the ability for the signal to travel faster forward. Up to 60 KMs +	This cable is used to transmit data to short distances. Because as the number of lights passes through the core, high dispersion and attenuation reduces the quality of the signal. Up to 2 KMs

SPX (Sequential Packet Exchange) Protocols

It is the version of Novels’ Sequenced Packet Protocol (SPP). It is a transport layer protocol and is used by client server applications. This protocol provides a packet delivery system for third party applications.

Figure given below illustrate the structure of SPX packet.

Connection Control Flag	DataStream Type
Source Connection ID
Destination Connection ID
Sequence Number
Acknowledge Number
Allocation Number
0-534 bytes of data

Connection Control Flag: Four flags are used to control bidirectional data flow of SPX connection. If its value is 1 flag is said to be set and if its value is 0 it is said to not set. Following are four flags:

Internetwork Packet Exchange (IPX)

Internetwork Packet Exchange (IPX) is a connectionless datagram protocol that is used by the Novell NetWare Operating System.  This protocol is the implementation of Xerox Network Systems’ IDP (Internet Datagram Protocols). It is Layer 3 protocol i.e. Network Layer Protocol.

IPX Protocol is very similar to the IP protocol. Some useful points about this protocol are as follows:

1)Unique 32 bit address is assigned to Logical Networks ranging from 0x1 to 0xFFFFFFFF (Hexadecimal).

2)48 bit node address is used by hosts, which is by default set to network card’s MAC address. Node address and network address are jointly used to identify the host on network.

3)00:00:00:00 means current network.

4)FF: FF: FF: FF is used as broadcast address.

Figure Given below Illustrates the IPX Packet.

Cheksum : Its value is set to FFFFH

Network Protocols and Their Functions

Protocols

Whenever a person want to talk with another person then their communicating language should be same so that they can easily communicate with each other .If they will use different languages then they can not understand what the other is saying. Similarly in Computer Networks certain rules are defined so that computers can communicate with one another.These Pre defined rules are called Protocols and can be defined as "Protocols are the predefined rules between the communicating devices that govern the communication between them."

Functions Of Protocols

i)  Sequencing of Data:- Protocols split large size messages to equal size pieces called Packets which can be transmitted easily.each packet contains unique identification number and can be easily arranged at receiver end to create original message.

ii) Flow Control of Data:-This is another important function of protocols.if sender is sending continuously data and receiver is not in a condition to receive that data or having less receiving speed then their are the chances of data loss.This data loss is avoided by the use of Protocols.

Difference Between LAN,MAN and WAN

Characteristics	LAN	MAN	WAN
Acronym	Local Area Network	Metropolitan Area Network	Wide Area Network
Cost	Less Costly	More Costly	Costliest
Speed	Up to 10-100Mbps	5-10Mbps	256Kbps to 2Mbps
Range	1Km	Up to 50 Kms.	Up to 10,000 Kms.
Topology	Bus and Ring	Distributed Queue Dual Bus [DQDB]	ATM, Frame Relay, Sonnet
Location of computers connected in the system	Computers are located within the same Building.	Computers are located in the city and are connected using modems or telephone lines so that they can be easily connected with Each other.	Computers are distributed all over the country or the Continent. The connection is made via satellite communication link Or via internet.

LAN,MAN and WAN

Local Area Network(LAN)

It is a computer network that interconnects computers in a limited area such as a home, school, computer laboratory, or office building using network media.
ARCNET, Token Ring and other technology standards have been used in the past, but Ethernet over twisted pair cabling, and Wi-Fi are the two most common technologies currently used to build LANs.

LAN is generally limited to specific geographical area less than 2 K.M., supporting high speed networks. A wide variety of LANs have been built and installed, but a few types have more recently become dominant. The most widely used LAN system is the Ethernet system based on the bus topology.
Intermediate nodes (i.e., repeaters, bridges and switches) allow

OSI Model

Open System Interconnection is a standard that describes how message  is transmitted and received between two points in telecommunication.It is developed by ISO( International Organization for Standardization ). It is a seven layer model and are labeled 1 to 7 with layer 1 at bottom(as per X.200 Recommendations).This concept of a seven-layer model was provided by the work of Charles Bachman, Honeywell Information Services.Idea behind this model was that the telecommunication between two points can be divided into layers with each layer adding its own set of special, related functions. The seven Layers are: 1)Physical Layer 2)Data Link Layer 3)Network Layer 4)Transport Layer 5)Session Layer 6)Presentation Layer 7)Application Layer. these seven layers are divided into two groups. The upper four layers are used whenever a message passes from or to a user(known as Host Layers). The lower three layers (up to the network layer) are used when any message passes through the host computer(known as Media Layers) . Messages intended for this computer pass

Network Topology

Network Topology is the arrangement of computers or nodes in the network.it describes how nodes are connected to each other in a network.There are two basic categories of network topologies:
i)Physical topologies
ii)Logical topologies
Physical Topologies:-The shape of the cabling layout used to link devices  in any network is referred to as physical topology of the network. This refers to the layout of cabling, the locations of nodes, and the interconnections between the nodes and the cabling.
Logical Topologies:-It is the way by which signals act on the network media, or  data passes through the network from one device to the next without regard to the physical interconnection of the devices.
Various Physical Topologies are:

Peer to Peer and Client Server Model

Client Server Model
Client Server model is a Networking Technique in which one of two roles are assigned  to the computers in a network: Client or server.server is a computer system that selectively shares its resources and provide services to its clients; client is a computer that make use of a resources with the help of server. Some features of this model are:
1)There will be atleast one Server and any no. of clients.
2)Server Provides services to clients.eg. if client 1 wants to access internet,then it will make request to server.server will check its rights and will provide access to internet as per rights assigned.Similarly if anybody wants to communicate with client 1 ,then it will authorized by server to gain access.
3)There is centralized controlling hub hence more security and rights assignment can be implemented.
4)Failure of Server will fail the entire network.
5)Clients and servers exchange messages in a request-response messaging pattern: The client sends a request, and the server returns a response.

Difference Between Hub Switch and Router

Hub	Switch	Router
In Hub signal introduced at the input of any port appears at the output of every port except the original  incoming. The device is a form of multiport repeater.	Network switch is a telecommunication device which receives a  message from any device connected to it and then transmits the message only to the device for which the message was meant. This makes the switch a more intelligent device than a hub	A router looks at packet headers to determine which port it needs to forward a packet through, and also will translate packets between different protocols if needed. A router can also define subnets and will filter traffic as needed. Routers usually include DHCP, port forwarding capabilities and a whole host of other things usually controlled by software and therefore user customizable.
A Hub is, in its simplest form, just like a mains multi plug unit. There is no intelligence or circuitry in it. More complex units may incorporate an amplifier or repeater. The network signal goes into one port and out of all the others.	A Switch has a small level of intelligence, in that it can open a message, check the IP address, and direct the message packets to the port on which the device with that IP address resides. It cannot modify IP addresses or see addresses outside of the range of the ‘home’ network	A Router can read IP addresses, and direct the messages to another network with different IP addresses to the originating network. The Router software can build up an address table, so that it ‘knows’ where other devices are.

Difference Between Synchronous and Asynchronous Transmission

Sr. No.	Synchronous Transmission	Asynchronous Transmission
1	Synchronous data transmission is a data transfer method in which a continuous stream of data signals is accompanied by timing signals (generated by an electronic clock) to ensure that the transmitter and the receiver are in step (synchronized) with one another. The data is sent in blocks (called frames or packets) spaced by fixed time intervals.	In contrast, asynchronous transmission works in spurts and must insert a start bit before each data character and a stop bit at its termination to inform the receiver where it begins and ends. The term asynchronous is used to describe the process where transmitted data is encoded with start and stop bits, specifying the beginning and end of each character.
2	It uses start and stop frames.	It uses start and stop bits.
3	Synchronous Transmission sends packets of characters at a time. Each packet is preceded by a Start Frame. This Start Frame is used to tell the receiving station that a new packet of characters is arriving, and it   synchronizes the receiving station’s internal clock. The packets also have End Frames to indicate the end of the packet.	Asynchronous Transmission sends only 1 character at a time. A character can be a letter of the alphabet, a  number or a control character. Preceding each character is a Start bit and ending each character is 1 or more Stop bits.

File Transfer Protocol(FTP)

File Transfer Protocol(FTP) is Networking Protocol that is used to transfer files from one host to another host based on TCP/IP Network.It Completely works on client server model and make use of separate data and control lines between server and client.User Requires username and password to connect or it may connect anonymously if  server is configured to do so.FTP is not able to encrypt its traffic; all transmissions are in clear text, and usernames, passwords, commands and data can be easily read by anyone able to perform packet capture.
This Protocol is totally transaction oriented.A transaction is defined to be an entity of information communicated between cooperating processes.Transaction has three fields:
1)72 bit Descriptor Field
2)Variable Length Data Field(Including Zero)
3)Variable length Filler Field
Hence,Transaction Length=(72 + data + filler) bits.

<Code> :This field has three 8 bit bytes. The first byte is interpreted as transaction type, the second byte as data type and the third byte as extension of data type.

Transmission Control Protocol(TCP)

Transmission Control Protocol(TCP) is a connection-oriented, end-to-end reliable protocol designed to fit into a layered hierarchy of protocols which support multi-network applications.the primary purpose of the TCP is to provide reliable, securable logical circuit or connection service between pairs of nodes.
following are some functions that are performed by TCP–>
i)Basic Data Transfer:-TCP is responsible to transfer a continuous stream of octets in each direction between its users by packaging some number of octets into segments for transmission through the internet system. TCPs decide when to block and forward data at their own convenience.
ii)Reliability:-The TCP  recovers data that is damaged, lost, duplicated, or delivered out of order by the internet communication system. To do so a sequence number to each octet transmitted, and requiring a positive acknowledgment (ACK) from the receiving TCP. If the ACK is not received within a timeout interval, the data is retransmitted. At the receiver, the sequence numbers are used to correctly order segments that may be received out of order and to eliminate duplicates. Damage is handled by adding a checksum to each segment transmitted, checking it at the receiver, and discarding damaged segments.